Question

the weight of 42 books is 7 kg. what is the weight of 60 such books

Answer 1

weight of 42 books=7kg
weight of 1 book=7/42×1=1/6
so, weight of 60 such books=1/6×60=10kg.

Answer 2

if weight of 42 books are 7 kg
then weight of 1 book is 7/42=1/6
now weight of 60 books =60×1/6=10
so , weight of 60 books are 10 kg.
I hope it will be helpful for you.